Light-out protection circuit



1939. L. D. DICKINSON ET AL 2,175,707

LIGHT-OUT PROTEGTIQN C IRCUIT Filed Aug. 17, 1958 2 Sheets-Sheet 1 v INVENTORS Leon 11D 'elizflzr'on 6 ZODH THEIR ATTORNEY 1939. D. DICKINSON HAL 2,176,707

LIGHT-OUT PROTECTION CIRCUIT Filed Aug. 17, 1938 2 Sheets-Sheet 2 IZZR 41 INVENTORS Leon 1). mm/m a M I c l l 7 THEIR ATTORNEY Patented Oct. 17, 1939 UNHTEB STATES ATENT OFFECE LIGHT-OUT PROTECTION CIRCUIT sylvania Application August 17,

20 Claims.

Our invention relates to railway signalling systems of the type employing light signals wherein the signals each comprise a plurality of lamps, and wherein when one lamp of a signal becomes burned out another lamp of that signal will become lighted to cause the signal to display a more restrictive indication.

An object of our invention is to provide an improved signal system of the type described and wherein a distinctive permissive indication is displayed at the entrance to an occupied block so that a train may enter such block without stopping, and wherein a stop indication is displayed if the permissive indication is not displayed when it should be.

A further object of our invention is to provide a system of the type described and in which if the lamp of the clear signal becomes burned out the lamp for giving a restrictive proceed indication will automatically be lighted in its place.

Another object of our invention is to provide a signal system of the type described and in which a plurality of lamps are employed to provide the permissive signal at the entrance of an occupied 25 block, and which system is arranged so that if either of the lamps for giving the permissive indication is burned out the stop indication will be displayed.

A further object of our invention is to provide an improved signal system of the type described.

Other objects of our invention and features of novelty will be apparent from the following description taken in connection with the accom. panying drawings.

We shall describe one form. of apparatus embodying our invention and shall then point out '38 novel features thereof in claims.

In the accompanying drawings Figs. A and 1B taaen together form a diagram illustrating a system embodying our invention.

Referring to the drawings, the reference nu-- merals l and 2 designate the rails of a stretch of railway track over which trafilc normally moves in the direction indiated by the arrows. The rails i and 2 are divided by insulated joints 3 into a pluraiity of track sections or blocks W-X and Each section is provided with a track battery 5 connected across the rails adjacent the exit end of the section, and with a track relay which is connected across the track rails adjacent the entrance end of the section.

Each of the track relays-is identified by the refeence character TR together with a prefix as for the signal for the section with which the track relay is associated.

1938, Serial No. 225,372

Located adjacent the entrance end of each section is a signal. The signals are designated by the reference characters HIS, HS and HS. As herein shown, each signal includes a proceed lamp G capable of displaying a green light, an upper yellow lamp Y capable of displaying a yellow light, a red lamp R capable of displaying a red light, and a lower yellow lamp Y capable of displaying a yellow light.

Each signal has associated therewith in addition to a track relay TR, a distant relay DR, an apprcach lighting relay AR, a first lightout relay LOR, a second lightout relay ZR, a transfer relay SR, and a source of energy in the form of a battery D.

The distant relay DR associated with each signal has one terminal of its winding connected to a branch of a wire 2@ leading to a common line CL which parallels the track stretch, While the wire 2% is also connected to a terminal of the battery D at that signal location. The other terminal of the winding of the relay DR associated with each signal is connected by a wire 55 to a movable contact 55 of the track relay TR associated with the same signal, and when this contact is picked up it engages a stationary contact to which is connected a wire 48 leading to the terminal of the winding of the approach lighting relay AR associated with the adjacent signal in advance. The other terminal of the winding of the approach lighting relay AR associated with each signal is connected by acircuit which is controlled by the contact of the track relay for that signal to a wire 2! which is connected to a terminal of the battery D at the signal location at which the approach lighting relay AR is located.

It will be seen, therefore, that the winding of approach lighting relay AR at each signal is connected to the battery at that signal in series with the relay DR associated with the adjacent signal in the rear, and that this circuit is controlled by the track relay associated with the signal with which the approach lighting relay is associated and also by the track relay associated with the signal of the adjacent block section in the rear. I v

The approach lighting relay AR for each signal controls a circuit from. which current is supplied to the yellow and green lamps for that signal, while the distant relay DR selectively controls the supply of current to the green and the upper yellow lamps of the signal with which the relay is associated. The relay DR also controls the circuit of the transfer relay SR, while the circuit f of the relay SR is further controlled by the relay ZR.

The lightout relay LOR operates to establish a circuit to the upper yellow light in the event that the green lamp is not lighted at a time at which it should be.

The transfer relay SR controls the circuits of the two yellow lamps and also controls a circuit for energizing its own winding, while the track relay TR for each section governs circuits for energizing both the upper and lower yellow lamps of the signal for that section.

Each of the relays ZR has a pair of windings, one of these being constantly connected in series with the lower yellow lamp, and the other being at times connected in series with the energizing circuit of the upper yellow lamp. The windings of each of the relays ZR are wound in opposition and are arranged so that when both are energized the contact of the relay will remain released, but so that if either winding is energized at a time when the other winding is not energized the relay contact will be picked up.

Having thus described in general the apparatus shown in the drawings, we shall now describe its operation.

When a train is in a block section the track relay TR of the adjacent signal in the rear (see signal I 25) is deenergized and its contacts engage their back points of contact to establish circuits to light both yellow lamps in series with the windings of the relay ZR, which circuits are also controlled by the contact of the approach lighting relay AR associated with the signal.

When the track relay at a signal is released the circuit of the approach lighting relay at that signal is interrupted, thereby completing the circuits to the yellow lamps at that signal, while the relay DR of the adjacent signal in the rear is deenergized as it is connected in series with the approach lighting relay AR.

When the relay DR is deenergized and the track relay is energized (see signal II S), which is the condition when there is only one clear block in advance of a signal, a circuit is established to light only the lamp of the upper yellow lamp, the circuit not being complete, however, until the approach lighting relay associated with that signal becomes released.

When the track relays at a signal and at the adjacent signal in the rear are both energized, that is when there are two clear blocks in advance of a signal, the circuit of the approach lighting relay AR at that signal and of the relay DR of the adjacent signal in the rear is complete with the result that these relays are both energized.

When the relay DR is energized (see signal HIS) a circuit is established to supply current to the green lamp G of the signal with which the relay DR is associated, this circuitnot being completed, however, until the approach lighting relay AR at that signal is released.

A train K is here shown diagrammatically at the right of location Y so that the track relay 'IZZTR is deenergized with the result that its contacts 25 and 26 engage their back points of contact and establish connections from wire 21 to light the lamps of both the upper and lower yellow lights of the signal IZS to indicate that the block section in advance of the signal is occupied.

The circuit for energizing the upper yellow lamp Y includes wire 2?, back point of contact 25 of relay i2TR, wire 28, lower winding 30 of relay IZZR, and wire M to a terminal of the upper yellow lamp Y, the other terminal of which is connected by a wire 32 to a front point of contact of relay IZSR. At this time the relay IZSR is energized and its contact 33 establishes a circuit to wire 3! from a branch of wire 2!] which is connected to a terminal of the battery I2D.

The circuit for energizing the lower yellow lamp Y includes wire 2i, contact 26 of relay IZTR, wire 38, upper winding 48 of relay IZZR, and wire 4! which is connected to a terminal of lower yellow lamp Y, the other terminal of which is connected by wire 32 to wire 28 and thus to a terminal of the battery 12D.

As the track relay IZTR is released due to the presence of a train in the section at the right of location Y, contact 35 of relay IZTR is released, thereby interrupting the circuit from wire 2|, which is connected to a terminal of battery I2D, to wire 36, which leads to a terminal of the winding of the approach relay iZAR. The winding of the approach lighting relay I2AR, therefore, is deenergized and its contact 52 engages its back point of contact to complete a circuit from wire 2|, leading from the battery I2D, to wire H which is connected to the movable contacts 25 and 26 of relay IZTR. The circuit for supplying current to the upper and lower yellow lamps of signal I2S, therefore, is complete and these lamps are lighted.

As long as the filaments of both lamps remain intact current continues to flow in the circuits of these filaments, and also in the windings 30 and 49 of relay I2ZR, with the result that these windings are both energized and the contact 43 of this relay remains in its released position and maintains the circuit from a branch of wire 29, leading from a terminal of the battery I213, to the wire 44 which is connected to one terminal of the winding of the relay IZSR.

At this time the circuit from the other terminal of the battery IZD to the other terminal of the winding of the relay iZSR is maintained through the wire 2! and a contact 45 of the relay IZSR.

As the contact 35 of relay IZTR is open the circuit of which the wire 48 leading from a terminal of the approach lighting relay IZAR to the winding of the relay I IDR forms a part is interrupted and the relay IIDR 'is released with the result that its contact 59 engages its back point of contact. The section X--Y being unoccupied, the track relay I ITR of this section is energized with the result that its contacts 25 and 26 are picked up and do not establish the circuits leading to the upper and lower yellow lamps.

Since the track section X-Y is not occupied, the track relay I ITR is energized, and as the contact 25 of track relay IITR is picked up it completes a circuit from wire 2i to wire 49, one branch of which is connected, through back point of contact 513 of relay IIDR to a branch of wire 3| leading to one terminal of the upper yellow light Y.

At this time the approach lighting relay I IAR is energized in a manner hereinafter explained in detail and its contact 52 is picked up and interrupts the connection of wire 21 to wire ZI leading from the battery I ED. Accordingly, even though contact 25 of IITR is picked up and connects wires El and 49, the Wire 49 is not energized. Energization-of wire 19 does not take place until a train enters block section WX and causes the release of approach lighting relay I IAR.

When this occurs the circuit to the upper yellow lamp is completed and may be traced from one terminal of the battery IID through wire 2|, contact 52 of relay IIAR, wire 21, contact 25 of relay II'I'R, wire 49, contact of relay HDR, wire 3|, upper yellow lamp Y, wire 32, contact 33 of relay HSR, and wire 20 to the other terminal of the battery I ID. When a train enters the block section W-X, therefore, and releases approach lighting relay HAR, the upper yellow lamp of the signal HS will be lighted to give the approach indication.

As the track relay H'IRis energized its contact 35 is picked up and connects wire 2|, leading from a terminal of battery IID, to wire 36 leading to a terminal of the winding of approach lighting relay HAR. The other terminal of this winding is connected by wire 48 to a stationary contact of track relay IOTR. The contacts of HlTR are picked up at this time as the track section WX is assumed to be unoccupied. The contact 55 of relay HJTR accordingly connects wire #8 to wire 55 leading to one terminal of the winding of relay IBDR. The other terminal of the winding of relay IUDR is connected by a branch of wire 29 to the common line CL and thereby to the battery I ID at signal is. A circuit is accordingly established to energize in series the approach lighting relay HAR, associated with signal I IS, and the relay IDDR associated with the signal ms with current supplied from the battery HD associated with the signal HS.

As relay IODR is energized its contact is picked up and connects wire 49 to wire 69 which is connected in series with the winding of the relay lfiLOR to a terminal of the green lamp G, the other terminal of which is connected by a branch of wire 20 to the battery HID. At this time as the contacts of relay IOTR are picked up, its contact 25 connects wire 2'! to wire 49, but as the approach lighting relay IElAR is assumed to be energized, its contact 52 does not connect wire 2'! to wire 2|, and thus to a terminal of the battery ID. The green lamp G of signal HIS is not illuminated as long as approach lighting relay HEAR is energized, but when the track section at the left of signal 193 becomes occupied, relay lilAR will be released and the contact 52' of this relay will complete the circuit to supply current from battery MD to light the green lamp G to provide the clear indication,

If the filament of the lamp G is intact the current flowing in the circuit of the lamp filament will energize the winding of the relay lElLOR and cause the contact 62 of this relay to be picked up, thereby interrupting connection between a branch of wire 49 and a branch of wire 3! leading to the upper yellow lamp.

At this time the contacts of track relay IIJTR are picked up and its contact 25 connects wire '2? to wire 9 with the result that when the contact 52 of approach lighting relay IOAR is released wire 49 is connected to wire 2! and thus to one terminal of battery 3D. However, as contact 62 of relay HlLOR is picked up as long as the green lamp G is lighted a circuit is not established from wire 49 to the upper yellow lamp Y while the green lamp remains lighted.

This system is arranged so that if the filament of the green light G becomes burned out and fails to provide a signal indication when current is supplied to the circuit of the lamp filament, the upper yellow lamp will automatically be lighted to give an approach indication instead of a clear indication.

Thus it will be seen that if the filament of the green lamp G should become burned out, thereby breaking the circuit of which the filament forms a part, the winding of the relay lllLOR will be deenergized and the contact 62 of this relay will be released, thereby completing a circuit from wire 49 to wire 3t, and thus to the upper yellow lam-p Y to light this lamp. The signal, therefore, will give the approach indication instead of the clear indication.

This system is also arranged so that in the event that the lamp of either of the yellow lights is burned out at a time when both lamps should be lighted, the lamp of the red light will be lighted and the lamp of the other yellow light will be extinguished.

Referring to the signal 12S, it will be seen that the upper yelow lamp Y is energized in series with the winding 39 of the relay lZZR, while the lower yellow lamp Y is energized in series with the winding 40 of the relay IZZR. As long as the filaments of both lamps remain intact, both windings of the relay IZZR are energized and the contact 43 of this relay remains released and maintains the circuit to the winding of the relay IZSR.

If, however, the filament of the lamp of either yellow light should be burned out, the winding of the relay lZZR which is connected in series with that filament will no longer be energized. The other winding of the relay IZZR, will be energized, however, and will cause the contact 43 of the relay IZZR to be picked up, thereby interrupting the circuit to the winding of the relay IZSR.

When the winding of the relay lZSR- is deenergized the contact 33 of this relay is released, thereby interrupting the connection from wire 29, leading from a terminal of battery IZD, to wire 32 leading to the upper and lower yellow lamps. At this time, therefore, the yellow lamp the filament of which remains intact will be eX-- tinguished, while the winding of the relay IZZR which is connected in series with that lamp filament will be deenergized, thereby releasing the contact 43 of relay lZZR. The contact 43, when released, will again connect a terminal of the winding of the relay IZSR to the wire 20 and thus to the battery IZD.

However, the circuit of the winding of the relay EZSR is interrupted at another point at this time, and the winding does not become energized when the contact 43 of relay IZZR. is

released.

It will be seen that when a train is in the block section at the right of signal I28, which is the situation when both yellow lamps are intended to be lighted, the relay l2TR is released and its contact 55 interrupts the circuit of the winding of the relay lZDR with the result that the relay IZDR is deenergized, Accordingly, the contact 63 of the relay EZDR is released and does not establish a circuit from wire 2! leading from one terminal of battery IZD to wire I5 3 leading to a terminal of the winding of relay 528R.

When the contact 53 of relay l2ZR became picked up and interrupted the circuit to the winding of the relay IZSR, the contact id or" relay IZSR became released, thereby interrupting the stick circuit from wire 25 to wire 64 leading to a terminal of the winding of relay lZSR. Accordingly, both connections from wire 2! to a terminal of the winding of the relay lZSR are interrupted, and when contact 43 of relay IZZR becomes released to again establish connection from wire 20 to the other terminal of the winding or" the relay IZSR, this winding will not be energized and the contacts of the relay 528R, will remain released.

When the contact 45 of relay IZSR is released it engages its back point of contact and establishes a circuit from wire 2| leading from battery IZD, to wire 66 leading to one terminal of the lamp of the red lamp R, the other terminal of which is connected by a branch of wire 26 to the other terminal of the battery i213. Ihe lamp R, therefore, becomes illuminated to give a stop signal.

In addition, it will be seen that as the contacts of relay IZSR are released its contact 33 interrupts the circuit connecting the upper and lower yellow lamps to one terminal of the battery l2D with the result that neither of these lamps can be energized until the contacts of relay 528R become picked up.

The relay IZDR, when released, will not become energized until the train K has advanced far enough to leave two clear blocks at the right of signal IZS. When the train advances this far the winding of relay IZDR will become energized over a circuit similar to that traced in connection with relay IODR. When the relay l2DR, is energized its contact 5!! establishes a circuit through which current may be supplied to light the lamp of the green light G of signal IZS, while the contact 63 of relay lZDR establishes a circuit from a terminal of the battery 52D through wire 2! to the wire 65 leading to the terminal of the winding of the relay lQSR.

The other terminal of the winding of the relay l'ZSR is connected by wire 44 and contact 43 of relay IEZR, to the other terminal of the battery lZD and the winding of. relay I ZSR, therefore, will be energized, and the contact 45 of the relay will be picked up and will complete the stick circuit to the relay winding so that the relay will thereafter remain energized until the contact 43 of relay IZDR again becomes picked up and interrupts the circuit of the winding of the relay l ZSR.

When the contact 45 of relay l2SR becomes picked up it interrupts the circuit to wire 66 leading to the red lamp R, thereby extinguishing this lamp.

When the contacts of relay IZSR are picked up the contact 33 of this relay again completes the circuit from a terminal of the battery lZD to wire 32 leading to the upper and lower yellow lamps. However, assuming that the defective lamp of the yellow light has not been replaced, when another train enters the block section at the right of signal I28 and releases the track relay EZTR, the contact 43 of relay l2ZR will again become picked up as only one winding of the relay 522R will be energized. When contact '33 is picked up the circuit to the winding of. relay EZSR is interrupted and the contact 33 interrupts the circuits of the yellow lamps, while the contact 35 again establishes a circuit to the red lamp.

It will be seen, therefore, that if either of the yellow lamps is burned out so that the normal permissive signal employed at the entrance to an occupied block is not displayed, when it should be, the red lamp will be li hted instead, and will remain lighted until two clear blocks in advance of the signal are provided, whereupon the red lamp will be extinguished, while a circuit is established to energize the green lamp, which circuit however, is not completed until the approach lighting relay is released.

Although we have herein shown and described only one form of apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, a section of railway track, a signal governing trafiic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a relay having a pair of windings, and means for energizing the filament of one of. said lamps in series with one of said relay windings and for simultaneously energizing the filament of the other of said lamps in series with the other of said relay windings, the relay having a contact which is picked up when and only when one of said relay windings is energized at a time at which the other of said relay windings is not energized, said signal having another lamp energized by a circuit established on picking up of said relay contact.

2. In combination, a section of railway track, a signal governing traliic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a relay having a pair of windings, and means for energizing the filament of one of said lamps in series with one of said relay windings and for simultaneously energizing the filament of the other of said lamps in series with the other of said relay windings, the relay having a contact which is picked up when and only when one of said relay windings is energized at a time at which the other of said relay windings is not energized, said signal having associated therewith other indication means controlled by said relay contact.

3. In combination, a signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a relay having a pair of windings, means for energizing the filament of one of said lamps in series with one of said relay windings and for simultaneously energizing the filament of the other of said lamps in series with the other of said relay windings, the relay having a contact which becomes picked up when and only when one of said relay windings is energized at a time at which the other of said relay windings is not energized, means operated on picking up of said relay contact for interrupting the circuits for energizing said lamp filaments and said relay windings, and another lamp associated with said signal andenergized by a circuit established on picking up of said relay contact.

4. In combination, a section of railway track, a signal governing trafiic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a relay having a pair of windings, means controlled by trafiic conditions in said section for energizing the filament of one of said lamps in series with one of said relay windings and for simultaneously energizing the filament of the other of said lamps in series with the other of said relay windings, the relay having a contact which becomes picked up when and only when one of said windings is energized at a time at which the other of said windings is not energized, whereby said relay contact becomes picked up in the event that the circuit of one relay winding is interrupted as a result of failure of the lamp filament which is connected in series therewith, said signal having associated therewith a third lamp which is supplied with energy by a circuit established on picking up of said relay contact;

5. In combination, a section of railway track, a signal governing traific in said section, said signal having a pair of lampseach having a filament, said lamps when both illuminated providing one signal aspect, a relay having a pair of windings, means controlled by trafiic conditions in said section for energizing the filament of one of said lamps in series with one of said relay windings and for simultaneously energizing the filament of the other of said lamps in series with the other of said relay windings, the relay having a contact which becomes picked up when and only when one of said windings is energized at a time at which the other of said windings is not energized, whereby said relay contact becomes picked up in the event that the circuit of one relay winding is interrupted as a result of failure of the lamp filament which is connected in series therewith, said signal having associated therewith other indication means controlled by said relay contact.

6. In combination, a-section of railway track, a signal governing traific in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a relay having a pair of windings, means controlled by traffic conditions in said section for energizing the filament of one of said lamps in series with one of said relay windings and for simultaneously energizing the filament of the other of said lamps in series with the other of said relay windings, the relay having a contact which becomes picked up when and only when one of said windings is energized at a time at which the other of said windings is not energized, whereby said relay contact becomes picked up in the event that the filament of one lamp is defective, thereby interrupting the circuit of one of the relay windings at a time when both windings should be energized, said signal having associated therewith other indication means controlled by said relay contact, and means controlled by traffic conditions in advance of said section for energizing the filament of one of said lamps by means of a circuit shunting the relay winding connected in series with said lamp filament.

7. In combination, a section or railway track, a signal governing traffic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated pro viding one signal aspect, a relay having a pair of windings, means controlled by traific conditions in said section for energizing the filament of one of said lamps in series with one of said relay windings and for simultaneously energizing the filament of the other of said lamps in series with the other of said relay windings, the relay having a contact which becomes picked up when and only when one of said windings is energized at a time at which the other of said windings is not energized, whereby said relay contact becomes picked up in the event that the filament of one lamp is defective, thereby interrupting the circuit of one of the relay windings at a time when both windings should be energized, said signal having associated therewith other indication means controlled by said relay contact, and means operative in the event of failure of another lamp of said signal for energizing the filament of one of said lamps by means of a circuit shunting the relay winding which is connected in series with said lamp filament.

8. In combination, a section of railway track, a signal governing trafiic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a lightout relay having a pair of windings and a contact which is picked up when and only when one of said windings is energized at a time when the other of the windings is not energized, a first supply circuit for energizing one of the windings of the lightout relay in series with the filament of one of the lamps, a second supply circuit for energizing the other of the windings of the lightout relay in series with the filament of the other of said lamps, means controlled by traffic conditions in said section for at times completing both of said supply circuits, a control relay controlled by the contact of the lightout relay and controlling said supply circuits, and other indication means controlled by said control relay.

9. In combination, a section of railway track, a signal governing traffic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a lightout relay having a pair of windings and a contact which is picked up when and only when one of said windings is energized at a time when the other of the windings is not energized, a first supply circuit for energizing one of the windings of the lightout relay in series with the filament of one of the lamps, a second supply circuit for energizing the other of the windings of the lightout relay in series with the filament of the other of said lamps, means controlled by traffic conditions in said section for at times completing both of said supply circuits, a control relay, means controlled by trafiic conditions in said section for establishing a circuit from one terminal of a source of current to one terminal of the control relay winding, the control relay having a contact operative when and only when. the relay winding is energized to also establish acircuit from said terminal of said source to said terminal of said relay winding, the contact of the lightout relay being operative when and only when released to establish a circuit from the other terminal of the source to the other terminal of the control relay winding, the control relay being operative when its winding is deenergized to interrupt both of said supply circuits, and other indication means controlled by said control relay.

10. In combination, a section of railway track, a signal governing traffic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a lightout relay having a pair of windings and a contact which is picked up when and only when one of said windings is energized at a time when the other of the windings is not energized, a first supply circuit for energizing one of the windings of the lightout relay in series with the filament of one of the lamps, a second supply circuit for energizing the other of the windings of the lightout relay in series with the filament of the other of Said lamps, means controlled by traific conditions in said section for at times completing both of said supply circuits, a control relay, means controlled by trafiic conditions in advance of said section for establishing a circuit from one terminal of a source of current to one'terminal'of the control relay winding, the control relay hav- 'be, and means controlled by traific conditions ing a contact operative when and only when the relay winding is energized to also establish a circuit from said terminal of said source to said terminal of said relay winding, the contact of the lightout relay being operative when and only when released to establish a circuit from the other terminal of the source to the other terminal of the control relay winding, the control relay being operative when its winding is deenergized to interrupt both of said supply circuits, and other indication means controlled by said control relay.

11. In combination, a section of railway track, a signal governing trafiic in said section, said signal having a first, a second, a third and a fourth lamp, said first and second lamps being simultaneously illuminated to provide one signal aspect, a lightout relay having a pair of windings, a first supply circuit for energizing the filament of the first lamp in series with one of 'said relay windings, a second supply circuit for lightout relay windings, means operative on picking up of the relay contact for energizing the third lamp, whereby said third lamp will become lighted in the event either of said first and second lamps is not lighted when it should in advance of said section for at times energizing the fourth lamp and at other times energizing the first lamp by a circuit shunting the relay winding which is connected in series with the filament of said lamp.

12. In combination, a section of railway track, a signal governing trafiic in said section, said signal having a first, a second, a third and a fourth lamp, said first and second lamps being simultaneously illuminated to provide one signal aspect, a lightout relay having a pair of windings, a first supply circuit for energizing the filament of the first lamp in series with one of said relay windings, a. second supply circuit for energizing the filament of the second lamp in series with the other of the relay windings, said relay having a contact which is picked up when and only when one of the relay windings is energized at a time at which the other winding is not energized, means controlled by traffic conditions in said section for at times completing both of said supply circuits to thereby energize said first and second lamps in series with said lightout relay windings, means operative on picking up of the relay contact for energizing the third lamp, whereby said third lamp will become lighted in the event either of said first and second lamps is not lighted when it should be, means controlled by traffic conditions in advance of said section for at times energizing the fourth lamp and at other times energizing the first lamp by a circuit shunting the relay winding which is connected in series with the filament of said lamp, and means responsive to the fiow of current in the circuit of the fourth lamp for controlling means for energizing the first lamp by a circuit shunting the relay winding which is connected in series with said lamp filament.

13. In combination, a section of railway track,

a source of current, a signal governing trafi'ic in said section, said signal having a first, a second, a third and a fourth lamp, said first and second lamps being simultaneously illuminated to provide one signal aspect, a lightout relay having a pair of windings, said relay having a contact which is picked up when and only when one of said relay windings is energized at a time at which the other winding is deenergized, a first supply circuit for energizing the filament of the first lamp in series with one of said relay windings, a second supply circuit for energizing the filament of the second lamp in series with the other of said relay windings, a third supply circuit, means controlled by trafiic conditions in said section for at one time establishing connection from one terminal of said source to said first and second supply circuits to thereby energize said first and second lamps in series with said lightout relay windings and for at another time establishing connection from said terminal of said source to said third supply circuit, means operative on picking up of said relay contact for energizing the third lamp, whereby said third lamp will become lighted in the event either of said first and second lamps is not lighted when it should be, and means controlled by traffic conditions in advance of said section for at times establishing connection from said third supply circuit to energize the fourth lamp and at other times to energize the first lamp by means of a circuit which shunts at the relay Winding which is connected in series with the filament of said lamp.

14. In combination, a section of railway track, a source of current, a signal governing traific in said section, said signal having a first, a second, a third and a fourth lamp, said first and second lamps being simultaneously illuminated to provide one signal aspect, a lightout relay having a pair of windings, said relay having a contact which is picked up when and only when one of said relay windings is energized at a time at which the other winding is not energized, a first supply circuit for energizing the filament of the first lamp in series with one of said relay windings, a second supply circuit for energizing the filament of the second lamp in series with the other of said relay windings, a third supply circuit, means controlled by traffic conditions in said section for at one time establishing connection from one terminal of said source to said first and second supply circuits to thereby energize said first and second lamps in series with said lightout relay windings and for at another time establishing connection from said terminal of said source to said third supply circuit, means operative on picking up of said relay contact for energizing the third lamp, whereby said third lamp will become lighted in the event either of said first and second lamps is not lighted when it should be, means controlled by trafiic conditions in advance of said section for at times establishing connection from said third supply circuit to energize the fourth lamp and at other times to energize the first lamp by means of a circuit which shunts at the relay winding which is connected in series with the filament of said lamp, and means responsive to fiow of current in the circuit of the fourth lamp-for establishing connection from the third supply circuit to energize the first lamp by means of a circuit which shunts the relay winding which is connected in series with the filament of said first lamp.

15. In combination, a section of railway track,

a source of current, a signal governing trafiic in said section, said signal having a first, a second, a third and a fourth lamp, said first and second lamps being simultaneously illuminated to provide one signal aspect, a lightout relay having a pair of windings, said relay having a contact which is picked up when and only when one of said relay windings is energized at a time at which the other winding is not energized, a first supply circuit for energizing the filament oi the first lamp in series with one of said relay windings, a second supply circuit for energizing the filament of the second lamp in series with the other of said relay windings, a third supply circuit, means controlled by traffic conditions in said section for at one time establishing connection from one terminal of said source to said first and second supply circuits to thereby energize said first and second lamps in series with said lightout relay windings and for at another time establishing connection from said terminal of said source to said third supply circuit, means operative on picking up of said relay contact for energizing the third lamp and for also con.- trolling said first and second supply circuits, whereby said third lamp will become lighted in the event either of said first and second lamps is not lighted when it should be, and means controlled by traffic conditions in advance of said section for at times establishing connection from said third supply circuit to energize the fourth lamp and at other times to energize the first lamp by means of a circuit which shunts at the relay winding which is connected in series with the filament of said lamp.

16. In combination, a section of railway track, a source of current, a signal governing traffic in said section, said signal having a first, a second, a third and a fourth lamp, said first and second lamps being simultaneously illuminated to provide one signal aspect, a lightout relay having a pair of windings, said relay having a contact which is picked up when and only when one of said relay windings is energized at a time at which the other winding is not energized, a first supply circuit for energizing the filament of the first lamp in series with one of said relay windings, a second supply circuit for energizing the filament of the second lamp in series with the other of said relay windings, 'a third supply circuit, means controlled by trafiic conditions in said section for at one time establishing connection from one terminal of said. source to said first and second supply circuits to thereby energize said first and second lamps in series with said lightout relay windings, and for at another time establishing connection from said terminal of said source to said third supply circuit, means operative on picking up of said relay contact and also controlled by trafiic conditions in advance of said section for energizing the third lamp and for controlling said first and second supply circuits, whereby said third lamp will become lighted in the event either of said first and second lamps is not lighted when it should be, and means controlled by trafiic conditions in advance of said section for at times establishing connection from said third supply circuit to energize the fourth lamp and at other times to energize the first lamp by means of a circuit which shunts at the relay winding which is connected in series with the filament of said lamp.

17. In combination, a section of railway track,

a signal governing trafiic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a first and a second control winding, means controlled by traific conditions in said section for energizing one of said lamp filaments in series with one of said control windings and for also energizing the other of said lamp filaments in series with the other of said control windings, said signal having a third lamp, and means controlled by said control windings for controlling the supply of current to said third lamp.

18. In combination, a section of railway track, a signal governing trafic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a first and a second control winding, and means controlled by traffic conditions in said section for energizing one of said lamp filaments in series with one of said control windings and for also energizing the other of said lamp filaments in series with the other of said control windings, said signal having a third lamp, and means controlled by said control windings for controlling the supply of current to said third lamp, said control windings also controlling the circuits for energizing said pair of lamps.

19. In combination, a. section of railway track, a signal governing traffic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a first and a second control winding, a first supply circuit for energizing the filament of one of said lamps in series with one of said control windings, a second supply circuit for energizing the filament of the other of said lamps in series with the other of said control windings, means controlled by traffic conditions in said section for energizing said first and second supply circuits, means controlled by traffic conditions. in advance of said section for energizing the filament of one of said lamps by a third supply circuit shunting the control winding associated with said lamp filament, said signal having a third lamp, and means controlled by said control windings for controlling the supply of current to said third lamp.

20. In combination, a section of railway track, a signal governing traffic in said section, said signal having a pair of lamps each having a filament, said lamps when both illuminated providing one signal aspect, a first and a second control winding, a first supply circuit for energizing the filament of one of said lamps in series with one of said control windings, a second supply circuit for energizing the filament of the other of said lamps in series with the other of said control windings, means controlled by trafiic conditions in said section for energizing said first and second supply circuits, means controlled by traffic conditions in advance of said section for energizing the filament of one of said lamps by a third supply circuit shunting the control winding associated with said lamp filament, said signal having a third lamp, and means controlled by said control windings for controlling the supply of current to said third lamp, said control windings also controlling said first and second supply circuits.

LEON D. DICKINSON. DAVID C. BETTISON. 

